examples/src/main/java/org/apache/spark/examples/ml/JavaBucketizerExample.java
<reponame>LexCC/spark-py/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.examples.ml;

import org.apache.spark.sql.SparkSession;

// $example on$
import java.util.Arrays;
import java.util.List;

import org.apache.spark.ml.feature.Bucketizer;
import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.RowFactory;
import org.apache.spark.sql.types.DataTypes;
import org.apache.spark.sql.types.Metadata;
import org.apache.spark.sql.types.StructField;
import org.apache.spark.sql.types.StructType;
// $example off$

/**
 * An example for Bucketizer.
 * Run with
 * <pre>
 * bin/run-example ml.JavaBucketizerExample
 * </pre>
 */
public class JavaBucketizerExample {
  public static void main(String[] args) {
    SparkSession spark = SparkSession
      .builder()
      .appName("JavaBucketizerExample")
      .getOrCreate();

    // $example on$
    double[] splits = {Double.NEGATIVE_INFINITY, -0.5, 0.0, 0.5, Double.POSITIVE_INFINITY};

    List<Row> data = Arrays.asList(
      RowFactory.create(-999.9),
      RowFactory.create(-0.5),
      RowFactory.create(-0.3),
      RowFactory.create(0.0),
      RowFactory.create(0.2),
      RowFactory.create(999.9)
    );
    StructType schema = new StructType(new StructField[]{
      new StructField("features", DataTypes.DoubleType, false, Metadata.empty())
    });
    Dataset<Row> dataFrame = spark.createDataFrame(data, schema);

    Bucketizer bucketizer = new Bucketizer()
      .setInputCol("features")
      .setOutputCol("bucketedFeatures")
      .setSplits(splits);

    // Transform original data into its bucket index.
    Dataset<Row> bucketedData = bucketizer.transform(dataFrame);

    System.out.println("Bucketizer output with " + (bucketizer.getSplits().length-1) + " buckets");
    bucketedData.show();
    // $example off$

    // $example on$
    // Bucketize multiple columns at one pass.
    double[][] splitsArray = {
      {Double.NEGATIVE_INFINITY, -0.5, 0.0, 0.5, Double.POSITIVE_INFINITY},
      {Double.NEGATIVE_INFINITY, -0.3, 0.0, 0.3, Double.POSITIVE_INFINITY}
    };

    List<Row> data2 = Arrays.asList(
      RowFactory.create(-999.9, -999.9),
      RowFactory.create(-0.5, -0.2),
      RowFactory.create(-0.3, -0.1),
      RowFactory.create(0.0, 0.0),
      RowFactory.create(0.2, 0.4),
      RowFactory.create(999.9, 999.9)
    );
    StructType schema2 = new StructType(new StructField[]{
      new StructField("features1", DataTypes.DoubleType, false, Metadata.empty()),
      new StructField("features2", DataTypes.DoubleType, false, Metadata.empty())
    });
    Dataset<Row> dataFrame2 = spark.createDataFrame(data2, schema2);

    Bucketizer bucketizer2 = new Bucketizer()
      .setInputCols(new String[] {"features1", "features2"})
      .setOutputCols(new String[] {"bucketedFeatures1", "bucketedFeatures2"})
      .setSplitsArray(splitsArray);
    // Transform original data into its bucket index.
    Dataset<Row> bucketedData2 = bucketizer2.transform(dataFrame2);

    System.out.println("Bucketizer output with [" +
      (bucketizer2.getSplitsArray()[0].length-1) + ", " +
      (bucketizer2.getSplitsArray()[1].length-1) + "] buckets for each input column");
    bucketedData2.show();
    // $example off$

    spark.stop();
  }
}


